The previous mark was just under eight years, but Purja took six months and six days, even finding time to rescue several fellow climbers. He also had to contend with having his oxygen stolen while on Lhotse, a neighboring peak to Mt. Everest.

Earlier this year, Purja shot to prominence when he photographed the "traffic jam" on the upper slopes of Everest (8,848m/29,029 feet) -- bringing global attention to the mountain's overcrowding.

But during his expeditions, the 36-year-old Purja says has also became acutely aware of the environmental changes the world is undergoing.

Over the space of a few years, the Nepalese has climbed several mountains in the Himalayas more than once. In doing so, Purja says he has seen the damaging effect of global warming.

"I climbed Dhaulagiri (8,167m) in 2014 and I went back again this year, the glacier is melting," Purja told CNN Sport. "You can see a huge difference. And even on Everest as well, the Khumbu glacier.

"In 2014, I climbed Ama Dablam (6,812m). In 2018, I was there again to climb Ama Dablam but the difference was that in 2014 we had snow at camp one, which we could melt and obviously cook food and drink.

"But in 2018, it was completely different. We had to carry gallons and gallons of water from the base camp. It was so hard. At that point, I realized this is really not on, and I have been raising awareness about it. The Earth is our home and we should look after it."

The importance of the mind

Previously, the fastest-known time for conquering the "8,000ers" was seven years, 10 months and six days, a record set by South Korean Kim Chang-ho in 2013.

Kim broke the first known record -- set by Polish climber Jerzy Kukuczka in 1987 -- by a month and eight days.

Climbing just one "8,000er," let alone all 14, is challenging enough given climbers are exposed to the "death zone" -- a mountaineering term that describes altitudes over about 8,000m where the human body is exposed to insufficient levels of oxygen.

In the build-up to Purja's attempt -- which he describes as an "extremely, horrendously good experience" -- he found he couldn't do much psychological preparation.

"I don't think you can really mentally prepare," he said. "There's not really set goals to it. In bigger missions like this, there will be so many obstacles, hurdles. There will be situations where you're like, 'OK, it's enough.' But if you just work around it, you need to have a positive mindset.

"My oxygen was stolen on Lhotse (8,516m) when I was going for the world record. If I would have gotten mad and said, 'Oh, somebody stole my oxygen,' and [been] just blaming people and just losing control of my mind, that would have a negative effect.

"But what I thought was I had to physically and positively inject in my mind for me to believe, 'Hey, that oxygen could have been used to save someone's life.'

"That's the positive message I had to feed through in my brain by myself in order to mitigate the negatives."

Helping others

Purja is a relatively inexperienced climber in comparison with his peers, having only completed his first major climb in 2012.

Previously a Gurkha soldier -- a Nepalese contingent of the British Army -- Purja progressed to the Special Boat Service (SBS), a British special forces unit under the auspices of the UK's Royal Navy, eventually quitting the military in 2018 as a Lance Corporal.

Since focusing on climbing completely, Purja admits that he's become "addicted," partly because it has helped put things into perspective. Such was his love for the expedition, he's also had the 14 "8,000ers" tattooed across his back.

"When I was in the Special Forces, you do really high value tasks," he recalls. "But the joy and the stuff and the pride that you do in that point was still the same, but nobody knew about it then.

"I still had three world records when I was in the Special Forces. Nobody knew, but now it's out and everybody kind of knew about it. Being completely honest, I don't really like this kind of popular life, but hey, I think it's part of life now."

Whilst speed was obviously of the essence during Purja's effort, the safety of the other climbers was always his priority.

The former soldier and his team also carried out a number of daring rescues, often putting their own lives in danger.

Just days into his journey, Purja and his team rescued Malaysian climber Chin Wui Kin after he had been reported missing on Annapurna.

"We opened the route that has never been climbed since 1970, summitted, got back to base camp and it was only three hours," he remembers. "We made the decision that we're not going to go to our next mountain, even though for this project, I had sacrificed my job, my pension, sold my house, everything.

"But for me, nothing is more important than life. We went and conducted the rescue. From where we're dropping down to where he was, on the summit day, it had taken us 18 hours to reach there, but actually when we did the rescue, we took only four hours.

"We were giving 100% of everything we had. We brought him down alive."

Tragically, after initially being treated in a hospital in Nepal's capital Kathmandu, Chin was airlifted to a hospital in Singapore, where he eventually succumbed to his injuries.

A band of brothers

Purja has been assisted during the remarkable 189-day feat by his all-Nepalese team, comprised of some of his most trusted climbing companions.

On top of helping Purja, his team have also been able to break their own records. One of his colleagues, Mingma David Sherpa, became the youngest person to complete all 14 peaks at the age of 30.

But after spending so much time together, Purja believes they are more than a team now.

"We started as a team, but now we are like brothers, we are like a family," he explains. "The bond and the relationship we have is unique.

"We kind of have a similar mortal mindset and aim. Everybody didn't really think that it was 'Nims' project', everybody thought that this is 'our project.'

A hot forecast continues Sunday for northwest Missouri and northeast Kansas with heat indicies anticipated to climb into the upper 90s - potentially 100s. Monday will also see temperatures in the low 90s.